From: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>
To: "Stephan Müller" <smueller@chronox.de>
Cc: herbert@gondor.apana.org.au, linux-crypto@vger.kernel.org,
Tianjia Zhang <tianjia.zhang@linux.alibaba.com>,
ard.biesheuvel@linaro.org, nhorman@redhat.com, simo@redhat.com
Subject: Re: [PATCH v3 0/5] DH: SP800-56A rev 3 compliant validation checks
Date: Tue, 21 Jul 2020 08:35:24 -0300 [thread overview]
Message-ID: <20200721113524.kdfs4nwn2oacexqx@valinor> (raw)
In-Reply-To: <2544426.mvXUDI8C0e@positron.chronox.de>
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Reviewed-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>
Tested-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>
On Mon, Jul 20, 2020 at 07:05:45PM +0200, Stephan Müller wrote:
> Hi,
>
> This patch set adds the required checks to make all aspects of
> (EC)DH compliant with SP800-56A rev 3 assuming that all keys
> are ephemeral. The use of static keys adds yet additional
> validations which are hard to achieve in the kernel.
>
> SP800-56A rev 3 mandates various checks:
>
> - validation of remote public key defined in section 5.6.2.2.2
> is already implemented in:
>
> * ECC: crypto_ecdh_shared_secret with the call of
> ecc_is_pubkey_valid_partial
>
> * FFC: dh_compute_val when the req->src is read and validated with
> dh_is_pubkey_valid
>
> - validation of generated shared secret: The patch set adds the
> shared secret validation as defined by SP800-56A rev 3. For
> ECDH this only implies that the validation of the shared secret
> is moved before the shared secret is returned to the caller.
>
> For DH, the validation is required to be performed against the prime
> of the domain parameter set.
>
> This patch adds the MPI library file mpi_sub_ui that is required
> to calculate P - 1 for the DH check. It would be possible, though
> to simply set the LSB of the prime to 0 to obtain P - 1 (since
> P is odd per definition) which implies that mpi_sub_ui would not
> be needed. However, this would require a copy operation from
> the existing prime MPI value into a temporary MPI where the
> modification can be performed. Such copy operation is not available.
> Therefore, the solution with the addition of mpi_sub_ui was chosen.
>
> NOTE: The function mpi_sub_ui is also added with the patch set
> "[PATCH v5 2/8] lib/mpi: Extend the MPI library" currently sent
> to the linux-crypto mailing list.
>
> - validation of the generated local public key: Patches 4 and 5 of
> this patch set adds the required checks.
>
> Changes to v2:
>
> - add reference to GnuMP providing the basis for patch 2 and updating
> the copyright note in patch 2
>
> Changes to v1:
>
> - fix reference to Gnu MP as outlined by Ard Biesheuvel
> - addition of patches 4 and 5
>
> Marcelo Henrique Cerri (1):
> lib/mpi: Add mpi_sub_ui()
>
> Stephan Mueller (4):
> crypto: ECDH - check validity of Z before export
> crypto: DH - check validity of Z before export
> crypto: DH SP800-56A rev 3 local public key validation
> crypto: ECDH SP800-56A rev 3 local public key validation
>
> crypto/dh.c | 38 +++++++++++++++++++++
> crypto/ecc.c | 42 +++++++++++++++++++++---
> crypto/ecc.h | 14 ++++++++
> include/linux/mpi.h | 3 ++
> lib/mpi/Makefile | 1 +
> lib/mpi/mpi-sub-ui.c | 78 ++++++++++++++++++++++++++++++++++++++++++++
> 6 files changed, 172 insertions(+), 4 deletions(-)
> create mode 100644 lib/mpi/mpi-sub-ui.c
>
> --
> 2.26.2
>
>
>
>
--
Regards,
Marcelo
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next prev parent reply other threads:[~2020-07-21 11:35 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-10 10:09 [PATCH 0/3] DH: SP800-56A rev 3 compliant shared secret Stephan Müller
2020-07-10 10:10 ` [PATCH 1/3] crypto: ECDH - check validity of Z before export Stephan Müller
2020-07-10 10:10 ` [PATCH 2/3] lib/mpi: Add mpi_sub_ui() Stephan Müller
2020-07-10 14:42 ` Ard Biesheuvel
2020-07-10 15:10 ` Stephan Mueller
2020-07-10 10:15 ` [PATCH 3/3] crypto: DH - check validity of Z before export Stephan Müller
2020-07-12 16:38 ` [PATCH v2 0/5] DH: SP800-56A rev 3 compliant validation checks Stephan Müller
2020-07-12 16:39 ` [PATCH v2 1/5] crypto: ECDH - check validity of Z before export Stephan Müller
2020-07-12 18:02 ` Vitaly Chikunov
2020-07-15 13:17 ` Marcelo Henrique Cerri
2020-07-12 16:39 ` [PATCH v2 2/5] lib/mpi: Add mpi_sub_ui() Stephan Müller
2020-07-16 7:30 ` Herbert Xu
2020-07-16 8:41 ` Ard Biesheuvel
2020-07-16 12:50 ` Marcelo Henrique Cerri
2020-07-16 13:09 ` Ard Biesheuvel
2020-07-16 13:41 ` Marcelo Henrique Cerri
2020-07-16 13:53 ` Ard Biesheuvel
2020-07-16 14:23 ` Marcelo Henrique Cerri
2020-07-16 14:37 ` Ard Biesheuvel
2020-07-16 14:56 ` Marcelo Henrique Cerri
2020-07-16 15:20 ` Ard Biesheuvel
2020-07-12 16:40 ` [PATCH v2 3/5] crypto: DH - check validity of Z before export Stephan Müller
2020-07-15 13:17 ` Marcelo Henrique Cerri
2020-07-12 16:40 ` [PATCH v2 4/5] crypto: DH SP800-56A rev 3 local public key validation Stephan Müller
2020-07-15 13:18 ` Marcelo Henrique Cerri
2020-07-12 16:42 ` [PATCH v2 5/5] crypto: ECDH " Stephan Müller
2020-07-12 18:06 ` Vitaly Chikunov
2020-07-13 5:04 ` Stephan Mueller
2020-07-13 5:59 ` Vitaly Chikunov
2020-07-13 6:02 ` Stephan Müller
2020-07-15 13:19 ` Marcelo Henrique Cerri
2020-07-20 17:05 ` [PATCH v3 0/5] DH: SP800-56A rev 3 compliant validation checks Stephan Müller
2020-07-20 17:07 ` [PATCH v3 1/5] crypto: ECDH - check validity of Z before export Stephan Müller
2020-07-22 13:11 ` Vitaly Chikunov
2020-07-24 17:47 ` Neil Horman
2020-07-20 17:08 ` [PATCH v3 2/5] lib/mpi: Add mpi_sub_ui() Stephan Müller
2020-07-20 17:08 ` [PATCH v3 3/5] crypto: DH - check validity of Z before export Stephan Müller
2020-07-24 18:02 ` Neil Horman
2020-07-20 17:08 ` [PATCH v3 4/5] crypto: DH SP800-56A rev 3 local public key validation Stephan Müller
2020-07-20 17:09 ` [PATCH v3 5/5] crypto: ECDH " Stephan Müller
2020-07-21 11:35 ` Marcelo Henrique Cerri [this message]
2020-07-31 13:29 ` [PATCH v3 0/5] DH: SP800-56A rev 3 compliant validation checks Herbert Xu
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